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Journal Articles

Devil's staircase transition of the electronic structures in CeSb

Kuroda, Kenta*; Arai, Yosuke*; Rezaei, N.*; Kunisada, So*; Sakuragi, Shunsuke*; Alaei, M.*; Kinoshita, Yuto*; Bareille, C.*; Noguchi, Ryo*; Nakayama, Mitsuhiro*; et al.

Nature Communications (Internet), 11, p.2888_1 - 2888_9, 2020/06

 Times Cited Count:3 Percentile:42.38(Multidisciplinary Sciences)

Journal Articles

Comparative study of oxidation on Cu and Cu$$_{3}$$Au surfaces with a hyperthermal O$$_{2}$$ molecular beam

Okada, Michio*; Moritani, Kosuke; Fukuyama, Tetsuya*; Mizutani, Hironori*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Toshio*

Surface Science, 600(18), p.4228 - 4232, 2006/09

 Times Cited Count:18 Percentile:63.36(Chemistry, Physical)

Dissociative adsorption of hyperthermal O$$_{2}$$ molecules on Cu$$_{3}$$Au(100) was investigated by X-ray photoemission spectroscopy in conjunction with a synchrotron light source. Comparing the O-uptake curve on Cu$$_{3}$$Au with that on Cu, it was found that the dissociative adsorption of O$$_{2}$$ is more activated (less reactive) due to Au alloying. The low-energy electron-diffraction (LEED) pattern of c(2$$times$$2) for the clean surface turned into the (1$$times$$1) LEED pattern during the oxidation by hyperthermal O$$_{2}$$ molecular beam, suggesting that the O adsorption induces the Cu-atom segregation on the surface.

Journal Articles

Synchrotron radiation photoelectron emission study of SiO$$_{2}$$ film formed by a hyperthermal O-atom beam at room temperature

Tagawa, Masahito*; Sogo, Chie*; Yokota, Kumiko*; Hachiue, Shunsuke; Yoshigoe, Akitaka; Teraoka, Yuden

Japanese Journal of Applied Physics, 44(12), p.8300 - 8304, 2005/12

 Times Cited Count:5 Percentile:22.76(Physics, Applied)

Si oxide layers formed on Si(001) substrates by irradiation of hyperthermal oxygen atomic beams at room temperature were analysed at the JAERI soft X-ray beamline by photoemission spectroscopy. It was found that sub-oxide components were scarcely observed in the Si oxide layers formed by the atomic oxygen beam.

Journal Articles

Synchrotron radiation photoabsorption and photoemission spectroscopy for thermal-induced reoriented Si polymer

Nath, K. G.; Shimoyama, Iwao; Sekiguchi, Tetsuhiro; Baba, Yuji

Journal of Electron Spectroscopy and Related Phenomena, 144-147, p.323 - 326, 2005/06

 Times Cited Count:5 Percentile:28.59(Spectroscopy)

The effect of laser annealing on electronic atructures and molecular orientation for poly(dimethylsilane), {PDMS, [Si(CH$$_{3}$$)$$_{2}$$]$$_{n}$$} has been studied by synchrotron radiation photoemission and photoabsorption spectroscopy. Prior to annealing, PDMS powder was mounted on the basal plane of highly oriented pyrolytic graphite. Both Si 1s X-ray photoemission spectroscopy and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at Si 1s edge show that electronic structures have been modified due to annealing. Furthermore, the angle-dependent NEXAFS spectra clearly indicate that the annealed products maintain a specific orientation. Interestingly, no such kind of orientation is present in as-received PDMS powder as no angle-dependency is observed before annealing.

Journal Articles

Synchrotron radiation photoemission spectroscopy for chemical bonding of N atoms in oxynitride films formed at SiO$$_{2}$$/Si(001) by N$$^{+}$$ beam irradiation

Hachiue, Shunsuke; Teraoka, Yuden

Shinku, 48(5), p.343 - 345, 2005/05

Silicon oxynitride layers were formed by irradiation of nitrogen ion beams at silicon substrates with ultrathin oxide layers. The nitrogen beam was mass-selected N$$^{+}$$ ion beam. The translational kinetic energy was about 3 keV. The dose was 6.3$$times$$10$$^{14}$$ ions/cm$$^{2}$$. This value is almost equal to the atom density at the Si(001) surface. Chemical bonding states of irradiated nitrogen atoms were analyzed by photoemission spectroscopy with synchrotron radiation. Although the nitrogen dose was a low density, N-1s photoemission spectra could be deconvoluted into four peaks. The chemical bonding state of each peak was assigned with a reference of a oxide layer thickness dependence of the N-1s photoemission peak profile.

Journal Articles

Analysis of surface chemical reaction dynamics by using high brilliance and high energy-resolution synchrotron radiation

Teraoka, Yuden

Denki Gakkai Gijutsu Hokoku, (970), p.10 - 15, 2004/07

Si(001) surfaces are oxidized by O$$_{2}$$ molecules. The reaction schemes (oxide-layers formation, SiO desorption, their coexistence) are changed depending on the surface temperature and the gas pressure. The translational kinetic energy of incident O$$_{2}$$ molecules is recognizing to be an important parameter for controlling surface chemical reactions. The issues concerning translational kinetic energy induced oxidation by O$$_{2}$$ molecules at room temperature, effects of translational kinetic energy for SiO desorption processes at higher temperature than 1000 K, reaction mechanisms for coexistence of the SiO desorption and the oxide-layers formation in the temperature region from 900 K to 1000 K are reviewed.

JAEA Reports

Initial oxidation of Ti(0001) surfaces induced by supersonic oxygen molecular beams

Ogawa, Shuichi*; Takakuwa, Yuji*; Ishizuka, Shinji*; Mizuno, Yoshiyuki*; Tonda, Hideki*; Homma, Teiichi*; Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke; Hachiue, Shunsuke

JAERI-Tech 2004-046, 25 Pages, 2004/06


We investigated the correlation between initial sticking coefficient and O$$_{2}$$ transitional kinetic energy to understand O$$_{2}$$ adsorption processes on the Ti(0001) surface via photoemission spectroscopy for O-1s and Ti-2p core levels using the surface reaction analysis apparatus, installed at the JAERI soft X-ray beamline BL23SU in the SPring-8. We observed the decrease of initial sticking coefficient of O$$_{2}$$ molecules on the Ti(0001) surface with increasing O$$_{2}$$ transitional kinetic energy. We concluded that the O$$_{2}$$ adsorption on the Ti(0001) surface proceeded by a trapping-mediated dissociative adsorption mechanism. The constant dependence of the initial sticking coefficient on incident angle of O$$_{2}$$ beams also suggested the propriety of the trapping-mediated surface reaction mechanism.

Journal Articles

High-resolution soft X-ray photoemission spectroscopy of spinel-type compound CuIr$$_{2}$$S$$_{4}$$

Okane, Tetsuo; Fujimori, Shinichi; Mamiya, Kazutoshi; Okamoto, Jun; Muramatsu, Yasuji; Fujimori, Atsushi; Suzuki, Hiroyuki*; Matsumoto, Takehiko*; Furubayashi, Takao*; Isobe, Masaaki*; et al.

Journal of Magnetism and Magnetic Materials, 272-276(Suppl.), p.e297 - e298, 2004/05

 Times Cited Count:5 Percentile:30.88(Materials Science, Multidisciplinary)

The electronic structure of spinel-type chalcogenide CuIr$$_{2}$$S$$_{4}$$, which exhibits a metal-insulator transition (MIT) as a function of temperature, has been studied by photoemission spectroscopy (PES). Below the transition temperature $$T_{mathrm{MI}}$$, the valence-band PES spectra indicate a gap formation, while the overall valence-band structure is shifted to the higher binding-energy side. The line shape of the Ir 4${it f}$ core-level PES spectra shows a dramatic change across $$T_{mathrm{MI}}$$, which may be associated with the variation of the Ir 5${it d}$ electron states.

Journal Articles

Chemical reaction dynamics in oxidation processes of Si(001) surface at high temperature

Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke

Shinku, 47(4), p.301 - 307, 2004/04

Recent research results on translational kinetic energy effects of incident oxygen molecules for Si(001) oxidation are summalized and introduced. The variation of surface temperature dependence of SiO desorption yield, oxygen uptake curves, and chemical bonding states depending on translational kinetic energy of oxygen molecules is described concretely. Eapecially, the translational kinetic energy effects on chemical reaction processes of concurrent oxide-layers formation and SiO desorption are discussed.

Journal Articles

Actively controlled oxidation of Cu{001} with hyperthermal O$$_{2}$$ molecular beam

Okada, Michio*; Moritani, Kosuke; Goto, Seishiro*; Kasai, Toshio*; Yoshigoe, Akitaka; Teraoka, Yuden

Journal of Chemical Physics, 119(14), p.6994 - 6997, 2003/10

 Times Cited Count:41 Percentile:79.17(Chemistry, Physical)

The oxidation of Cu(001) with hyperthermal O$$_{2}$$ molecular beams was investigated using X-ray photoemission spectroscopy in conjunction with a synchrotron light source. The efficiency of oxidation is higher than that with ambient thermal O$$_{2}$$. Further oxidation under oxygen coverage larger than 0.5 ML occurs rather inefficiently even for the 2.3 eV beam irradiation. We found such slow oxidation of Cu corresponding to the initial stage of the Cu$$_{2}$$O formation can be interpreted in terms of a collision-induced-adsorption mechanism. The kinetics of the dissociative adsorption is well described using the first order kinetics in a simple Langmuir-type adsorption model.

Journal Articles

Oxidation of aqueous HF-treated Si(001) surface induced by translational kinetic energy of O$$_{2}$$ at room temperature

Yoshigoe, Akitaka; Teraoka, Yuden

Japanese Journal of Applied Physics, Part 1, 42(9A), p.5749 - 5750, 2003/09

 Times Cited Count:2 Percentile:11.17(Physics, Applied)

We investigated oxidation reactions induced by the translational kinetic energy of O$$_{2}$$ on an Si(001) surface treated with aqueous hydrofluoric acid (HF) solution by combining synchrotron radiation photoemission spectroscopy with supersonic molecular beam techniques. The oxidation reactions at room temperature did not progress following up to approximately 3600 L exposure of O$$_{2}$$ with incident energy of 0.04 eV. On the other hand, the oxidation states up to the Si$$^{4+}$$ species including the Si$$^{1+}$$, Si$$^{2+}$$ and Si$$^{3+}$$ species were formed when the incident energy was 3.0 eV. The thickness of oxidized layers was estimated to be 0.26 nm at the final oxidation stages. Thus, we concluded that the Si atoms at the top layers were oxidized by the translational kinetic energy of 3.0 eV.

Journal Articles

In-situ observation of growth of very thin oxide on Ti surfaces by real-time photoelectron spectroscopy

Takakuwa, Yuji*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden

Kagaku Kogyo, 54(9), p.687 - 692, 2003/09

Real-time in-situ photoemission spectroscopic studies on Ti(0001) oxidation by O$$_{2}$$ molecules at 473K-673K are reviewed. The Ti(0001) surface was changed from metal to oxide during exposure to oxygen gas. From the time dependent Ti-2p photoemission spectra, time evolution of each oxide component of Ti was clarified.

Journal Articles

SiO mass spectrometry and Si-2p photoemission spectroscopy for the study of oxidation reaction dynamics of Si(001) surface by supersonic O$$_{2}$$ molecular beams under 1000 K

Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke

Japanese Journal of Applied Physics, Part 1, 42(7B), p.4671 - 4675, 2003/07

 Times Cited Count:4 Percentile:20.93(Physics, Applied)

The oxidation reaction mechanisms for Si(001) by O$$_{2}$$ molecules have been investigated in a surface temperature region from 860 K to 1300 K and in an incident energy region from 0.6 eV to 3.0 eV. Synchrotron Radiation photoemission spectroscopy was used for surface analysis. Si-2p photoemission spectra were measured during molecular beam irradiation so that their dependences on surface temperature and incident energy were clarified. SiO molecules, desorbed from the surface at high temperature region, were also detected by a quadrupole mass analyzer using $$^{18}$$O$$_{2}$$ molecular beams to measure SiO desorption yield depending on surface temperature and incident energy. Consequently, a reaction scheme, oxide layers formation, etching, and coexistence of both reactions, is determined by the incident energy under 1000 K.

Journal Articles

Real-time observation of initial stage on Si(001) oxidation studied by O-1s photoemission spectroscopy using synchrotron radiation

Yoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden

Japanese Journal of Applied Physics, Part 1, 42(7B), p.4676 - 4679, 2003/07

 Times Cited Count:1 Percentile:5.92(Physics, Applied)

Many studies of the thermal oxidation on Si(001) surface by O$$_{2}$$ gas have been already carried out from both experimental and theoretical methods. The oxidation reaction kinetics have been studied by real time photoemission spectroscopy. Most reports, however, were performed at a fixed electron binding energy. We present the study of initial stage of thermal oxidation on Si(001) surface at the O$$_{2}$$ pressure of 1x10$$^{-4}$$ Pa performed by real time O-1s synchrotron radiation photoemission spectroscopy.All experiments were performed at SUREAC2000 at BL23SU in the SPring-8. The pure O$$_{2}$$ gas of 1x10$$^{-4}$$ Pa was fed into the reaction analysis chember through a variable leak valve. The results of oxygen uptake curves obtained by O-1s peak area intensities at the substrate temperature of 855K and 955K indicate that the Langmuir adsorption model provided the best fitting result for the 855K oxidation, whereas the oxidation at 955K was well explained by the autocatalytic reaction model.

Journal Articles

Photoemission spectroscopy of the filled skutterudite compound YbFe$$_{4}$$Sb$$_{12}$$

Okane, Tetsuo; Fujimori, Shinichi; Mamiya, Kazutoshi; Okamoto, Jun; Muramatsu, Yasuji; Fujimori, Atsushi; Nagamoto, Yasuyuki*; Koyanagi, Tsuyoshi*

Journal of Physics; Condensed Matter, 15(28), p.S2197 - S2200, 2003/07

 Times Cited Count:4 Percentile:27.78(Physics, Condensed Matter)

The filled skutterudite compounds $$RT_{4}X_{9}$$ ($$R$$ = alkaline earth, rare earth, actinide; $$T$$ = Fe, Ru, Os; $$X$$ = pnictogen: P, As, Sb) exhibit a variety of physical properties such as superconductivity, magnetic ordering, heavy-Fermion behavior, and metal-insulator transition. Among them, YbFe$$_{4}$$Sb$$_{12}$$ shows a heavy-Fermion or intermediate-valence behavior in the magnetic, electrical transport, and thermal properties, which might be associated with a valence instability of Yb atom. In this study, the electronic structure of YbFe$$_{4}$$Sb$$_{12}$$ have been investigated by the high-resolution photoemission spectroscopy, using He discharge lamp and synchrotron radiation as an excitation sources. The bulk and surface components of the Yb$$^{2+}$$ signal is clearly divided in the spectra. The relation of the energy position between them is anomalous compared to that of the conventional mixed-valent Yb compounds.

Journal Articles

Coexistence of passive and active oxidation for O$$_{2}$$/Si(001) system observed by SiO mass spectrometry and synchrotron radiation photoemission spectroscopy

Teraoka, Yuden; Moritani, Kosuke; Yoshigoe, Akitaka

Applied Surface Science, 216(1-4), p.8 - 14, 2003/06

 Times Cited Count:6 Percentile:36.6(Chemistry, Physical)

The experiments concerning the oxidation of Si(001) were performed at the surface reaction analysis apparatus, installed at the beamline BL23SU in the SPring-8. The SiO desorb remarkably at surface temperature of 1000 K. The desorption yield increased with increasing the incident energy of O$$_{2}$$. On the other hand, the desorption yield increased with decreasing the incident energy in the temperature region lower than 1000 K. Oxygen uptake curves observed by O-1s photoemission measurements corresponded to the SiO desorption features. These facts reveal that the passive oxidation coexists with the SiO desorption in the temperature region from 900 K to 1000 K.

Journal Articles

Real time observation of initial thermal oxidation using O$$_{2}$$ gas on Si(0 0 1) surface by means of synchrotron radiation Si-2p photoemission spectroscopy

Yoshigoe, Akitaka; Moritani, Kosuke; Teraoka, Yuden

Applied Surface Science, 216(1-4), p.388 - 394, 2003/06

 Times Cited Count:9 Percentile:47.17(Chemistry, Physical)

It is well known that the initial Si(0 0 1) oxidation by O$$_{2}$$ gas is an important reaction system because it is usually used to form gate-oxide films on MOSFET. With decreasing the size of ULSI, it is necessary to control the surface reaction with atomic scales. In this study, we report ${it the real time in-situ}$ observation of thermal oxidation using O$$_{2}$$ gas on Si(0 0 1) surface by means of synchrotron radiation photoemission spectroscopy at the soft x-ray beamline, BL23SU, in the SPring-8. We clarified the chemisorption processes of O$$_{2}$$ on Si(0 0 1) surface over 773K regions at the initial oxidation stages from the results of Si2p core-level shifts. The fundamental understanding of surface reaction is expected to contribute the development of the future nanotechnology.

Journal Articles

Prominent quasiparticle peak in the photoemission spectrum of the metallic phase of V$$_{2}$$O$$_{3}$$

Mo, S.-K.*; Denlinger, J. D.*; Kim, H.-D.*; Park, J.-H.*; Allen, J. W.*; Sekiyama, Akira*; Yamasaki, Atsushi*; Kadono, Koji*; Suga, Shigemasa*; Saito, Yuji; et al.

Physical Review Letters, 90(18), p.186403_1 - 186403_4, 2003/05


 Times Cited Count:134 Percentile:95.62(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Control of O$$_{2}$$ adsorption and SiO desorption by incident energy of O$$_{2}$$ molecules in the O$$_{2}$$/Si(001) surface reaction system

Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke

Atomic Collision Research in Japan, No.29, p.68 - 70, 2003/00

There are two surface chemical reaction modes in the O$$_{2}$$/Si(001) system, that is, oxide-layers formation and SiO desorption. We have found that these reaction modes could be selected by changing translational kinetic energy of incident O$$_{2}$$ molecules.

Journal Articles

In-situ photoemission spectroscopy for chemical reaction dynamics study of Si(001) oxidation by using high-energy-resolution synchrotron radiation

Teraoka, Yuden; Yoshigoe, Akitaka

Oyo Butsuri, 71(2), p.1523 - 1527, 2002/12

The translational kinetic energy of incident molecules is an important parameter for the study of surface chemical reaction mechanisms. New adsorption reactions, induced by the O$$_{2}$$ translational kinetic energy of several eV, have been found in the O$$_{2}$$/Si(001) system by applying the surface photoemission spectroscopy with supersonic molecular beam techniques and the high-energy-resolution synchrotron radiation. The termination of dangling bonds affected dominantly the oxidation of dimer backbonds. By controlling the translational kinetic energy of incident O$$_{2}$$ molecules, the formation of oxide-layers with a sub-nanometer scale is possible at room temperature.

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